For aluminum supports used in lithographic printing plates, it is known that a surface of an aluminum support is grained (i.e., subjected to surface roughening treatment) to provide asperities for the purpose of improving scumming resistance and a press life of the resulting lithographic printing plate.
For instance, Patent Literature 1 describes “a support for a lithographic printing plate which, when measured over a 400 μm×400 μm surface region thereon using a three-dimensional non-contact roughness tester, has at most 5.0 convex portions of a height from centerline of at least 0.70 μm and an equivalent circle diameter of at least 20 μm, and has at least 800 concave portions of a depth from centerline of at least 0.50 μm and an equivalent circle diameter of at least 2.0 μm” (claim 1), as well as a lithographic printing plate precursor comprising the support for a lithographic printing plate as above and an image recording layer thereon (claim 3).